Well, these Dover editions have always been a good choice for music teachers and composers who don't want to spend on an expensive book, but who would like to have these scores available for reference and orchestration technique analysis. The covers are always handsome, and the books will stay in good condition if treated with care.
In my case, I was especially interested in how Tchaikovsky orchestrated the overture to the sleeping beauty, which has always seemed to me as an overture of surpassing dramatic power combined with a wonderful epic, fairy tale like atmosphere, foreshadowing scenes to come. I was surprised by some details I discovered when I finally had the score in my hands, like the way Tchaikovsky added two cornets to the brass section, in addition to the usual two trumpets, and the spectacular crashing sound in the middle is not a gong (as I thought) but a "tam tam", played very loudly. That is the part where the evil fairy arrives into the castle, but Tchaikovsky put such a strength into this moment that it would be easy to picture mighty dragons descending into the hall, instead of just one evil witch (no matter how evil).
These books contains some of the best moments of both ballets, so it is an excellent introduction into these work's orchestration. If I wanted a complete Tchaikovsky ballet, I would rather choose the nutcracker, and indeed I did (Dover has a complete print of this one). I don't care what anybody says on the subject, I'm convinced The Nutcracker is the best of the three. But there is no denying that Swan Lake and Sleeping Beauty have many great musical moments, impossible to ignore.